py38 ReplicationTestCase unit test failure

Spotted on
https://review.opendev.org/c/openstack/cinder/+/733621/14/

which is one (presumably unrelated) patch on top of HEAD @ d3ffa90baa959.

Test fails because the "availability_zone" field in this call does not match. ("cinder" vs. "nova")

cinder.tests.unit.volume.test_replication_manager.ReplicationTestCase.test_failover_manager_2_cluster_name
----------------------------------------------------------------------------------------------------------

Captured traceback:
~~~~~~~~~~~~~~~~~~~
    Traceback (most recent call last):

      File "/home/zuul/src/opendev.org/openstack/cinder/.tox/py38/lib/python3.8/site-packages/ddt.py", line 182, in wrapper
    return func(self, *args, **kwargs)

      File "/usr/lib/python3.8/unittest/mock.py", line 1325, in patched
    return func(*newargs, **newkeywargs)

      File "/home/zuul/src/opendev.org/openstack/cinder/cinder/tests/unit/volume/test_replication_manager.py", line 286, in test_failover_manager
    finish_mock.assert_called_once_with(self.context, svc, expected_update)

      File "/usr/lib/python3.8/unittest/mock.py", line 925, in assert_called_once_with
    return self.assert_called_with(*args, **kwargs)

      File "/usr/lib/python3.8/unittest/mock.py", line 913, in assert_called_with
    raise AssertionError(_error_message()) from cause

    AssertionError: expected call not found.
Expected: finish_failover(<cinder.context.RequestContext object at 0x7f2f068bd280>, Service(active_backend_id=None,availability_zone='cinder',binary='cinder-volume',cluster=<?>,cluster_name='cluster_name',created_at=2020-12-09T19:54:27Z,deleted=False,deleted_at=None,disabled=False,disabled_reason=None,frozen=False,host='ubuntu-focal-rax-ord-0022137034',id=1,modified_at=None,object_current_version=None,replication_status='enabled',report_count=0,rpc_current_version=None,topic=None,updated_at=2020-12-09T19:54:27Z,uuid='191bbf1e-3446-46b3-8e6c-63b6bd880d43'), {'replication_status': 'failed-over', 'active_backend_id': 'secondary', 'disabled': True, 'disabled_reason': 'failed-over'})
Actual: finish_failover(<cinder.context.RequestContext object at 0x7f2f068bd280>, Service(active_backend_id=None,availability_zone='nova',binary='cinder-volume',cluster=<?>,cluster_name='cluster_name',created_at=2020-12-09T19:54:27Z,deleted=False,deleted_at=None,disabled=False,disabled_reason=None,frozen=False,host='ubuntu-focal-rax-ord-0022137034',id=1,modified_at=None,object_current_version=None,replication_status='enabled',report_count=1,rpc_current_version=None,topic=None,updated_at=2020-12-09T19:54:27Z,uuid='191bbf1e-3446-46b3-8e6c-63b6bd880d43'), {'replication_status': 'failed-over', 'active_backend_id': 'secondary', 'disabled': True, 'disabled_reason': 'failed-over'})